scholarly journals Enhanced Scratch Performance of Plasma Sprayed Hydroxyapatite Composite Coatings Reinforced with BN Nanoplatelets

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 652
Author(s):  
Yao Chen ◽  
Jia Ren ◽  
Weiwei Liu ◽  
Dong Zhao
Keyword(s):  
Hexagonal Boron Nitride ◽  
Dominant Role ◽  
Composite Coatings ◽  
Surface Damage ◽  
Lateral Force ◽  
Ha Coating ◽  
Hydroxyapatite Composite ◽  
Brittle Fractures ◽  
Plasma Sprayed

In recent years, research on hydroxyapatite (HA) coatings has been driven by the demands of clinical applications. However, the intrinsic brittleness of HA limits its potential in the use for the load-bearing implant. To improve mechanical properties of the HA coating itself, a HA composite coating reinforced with hexagonal boron nitride nanoplatelets (BNNP) was fabricated using plasma spray, and its scratch behavior was investigated in this research. Typical brittle fractures such as microcracks both in and beyond the residual groove and material chipping were observed in the HA coating, while stronger and tougher BNNP/HA coatings exhibited a dominant role in protecting them from scratch damage through resisting plastic deformation and brittle microfracturing. Moreover, easier grain sliding within a splat and splat sliding at the splat boundaries due to the presence of BNNPs, and the nature porosity at different length scales of the as-sprayed HA composite coatings would provide significant self-lubricating effects to reduce the lateral force during scratching and alleviate the contact damage. Therefore, the addition of BNNPs renders HA coating with low scratch friction and enhanced tolerance to surface damage, which is naturally beneficial for the long-term durability and reliability of the implants.

Improve Stability of Dicalcium Silicate/Zirconia Composite Coatings by Post-Spraying Heat Treatment

2005 ◽  
Vol 107 ◽  
pp. 141-144 ◽  
Author(s):  
Youtao Xie ◽  
Paul K. Chu ◽  
Xuan Yong Liu ◽  
Chuan Xian Ding
Keyword(s):  
Heat Treatment ◽  
Composite Coatings ◽  
Immersion Test ◽  
Dicalcium Silicate ◽  
Test Results ◽  
Long Term Stability ◽  
The Stability ◽  
Plasma Sprayed ◽  
Sprayed Coatings

The long-term stability of plasma-sprayed dicalcium silicate (C2S) composite coatings is determined by the phase composition, crystallinity, and other properties. Zirconia reinforcement and post-spraying heat treatment are applied to C2S coatings simultaneously in this work. The stability of the coating increases evidently by reinforcement with 70wt% zirconia and heat treatment at 800oC for 4 hours. SEM reveals that the smooth glassy surface of the as-sprayed coatings is replaced by randomly dispersed crystals. Tris-HCl immersion test results show that the dissolution rate of the composite coatings decreases after the heat treatment.

Characterization of HA/Ta Composite Coatings Fabricated by Vacuum Plasma Spraying

2013 ◽  
Vol 761 ◽  
pp. 113-116 ◽  
Author(s):  
Li Ping Huang ◽  
You Tao Xie ◽  
Heng Ji ◽  
Yi Zeng ◽  
Xue Bin Zheng
Keyword(s):  
Plasma Spraying ◽  
Bonding Strength ◽  
Composite Coatings ◽  
X Ray Diffraction ◽  
Vacuum Plasma Spraying ◽  
Vacuum Plasma ◽  
Plasma Sprayed ◽  
Bonelike Apatite

Plasma sprayed hydroxyapatite (HA) coatings on titanium alloy substrates have been used extensively due to their excellent biocompatibility and osteoconductivity. However, the low bonding strength between HA and Ti substrates is still problematic in the long-term implantation lifespan. In this paper, HA/Ta composite coatings with various Ta contents (20% and 60%) were fabricated by vacuum plasma spraying (VPS). The microstructure, phase composition of the coatings was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The results revealed that the coatings had a rough surface and lamellar structure including some pores. ASTM C-633 standard was used for the measurement of bonding strength, which was found increasing with the increase of Ta contents in the composite coatings. The bonding strength of the composite coating containing 60% Ta (H4T6) reached to 37.2 MPa, which is about 1.9 times that of HA coating. In vitro bioactivity evaluated in simulated body fluids (SBF) showed that bonelike apatite layer was formed on the composite coatings surface, which indicated the good bioactivity of the HA/Ta composite coatings.

EFFECT OF STAND-OFF DISTANCE ON STRUCTURE AND MECHANICAL PROPERTIES OF HYDROXYAPATITE COATINGS PLASMA-SPRAYED ONTO CARBON/CARBON COMPOSITES

2007 ◽  
Vol 14 (03) ◽  
pp. 371-376 ◽  
Author(s):  
JIN-LING SUI ◽  
WU BO ◽  
ZHOU HAI ◽  
NING CAO ◽  
MU-SEN LI
Keyword(s):  
Shear Strength ◽  
Phase Composition ◽  
Plasma Spraying ◽  
Cross Sections ◽  
Dominant Role ◽  
Power Level ◽  
Carbon Composites ◽  
Ha Coating ◽  
Hydroxyapatite Coatings ◽  
Plasma Sprayed

Plasma-spraying parameters are of crucial importance to the fabrication of high-quality hydroxyapatite (HA) coating for biomedical use. In this paper, hydroxyapaptite was coated onto carbon fiber reinforced carbon composites ( C/C composites) by a plasma spraying method. The effect of stand-off distances on the microstructure, phase composition and shear strength of hydroxyapatite coatings was studied. X-ray diffraction (XRD) was used to characterize the phase composition and scanning electron microscopy (SEM) examined the morphology of the sprayed surface and polished cross-sections. The shear strength of the HA coatings– C/C substrates was detected on a RGD-5 electric tension machine. The interface of the HA coating– C/C composites was also detected. Results showed that the extent of melting of particles increased with increasing stand-off distances, while the crystallinity of the HA decreased at a power level of 30 kW. Mechanical bonding plays a dominant role at the interface of the rough substrate and the deformed HA particles.

Plasma Sprayed Zirconia-Hydroxyapatite Composite Coatings

2006 ◽  
pp. 631-634 ◽  
Author(s):  
M.M. Aydın ◽  
L.S. Ozyegin ◽  
Faik N. Oktar ◽  
E.Z. Erkmen ◽  
O. Anzabi ◽  
...  
Keyword(s):  
Composite Coatings ◽  
Hydroxyapatite Composite ◽  
Plasma Sprayed

scholarly journals Microstructural Charactistics of Plasma Sprayed NiCrBSi Coatings and Their Wear and Corrosion Behaviors

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 170
Author(s):  
Songqiang Huang ◽  
Jingzhong Zhou ◽  
Kuoteng Sun ◽  
Hailiang Yang ◽  
Weichen Cai ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Acid Corrosion ◽  
Composite Coatings ◽  
Atmospheric Plasma ◽  
Confocal Laser ◽  
Formation Mechanisms ◽  
Temperature Oxidation ◽  
Surface Protection ◽  
Plasma Sprayed ◽  
Nicrbsi Coatings

Nickel-based alloys are commonly used as protective coating materials for surface protection applications owing to their superior resistance to corrosion, wear and high-temperature oxidation. It is urgent to study the fundamental mechanism between the structure and corrosion properties of the Nickel-base composite coatings. This paper, therefore, focuses on clarifying the mechanisms of the microstructure influencing the acid corrosion and mechanical characteristics of the as-sprayed NiCrBSi coating and post-heat-treated coating. The formation mechanisms of the amorphous phase of flat particles during the plasma spray process were studied by using X-ray diffraction analysis, Raman spectroscopy and confocal laser scanning microscope at first. Then the evolutionary process of the corrosion structure and phase of the coating in the accelerated corrosion experiment is directly visualized by using scanning electron microscopy and energy spectrum analysis. The mechanical properties of the amorphous NiCrBSi coatings are lastly measured by microhardness and friction wear tests. The critical phenomena and results help to elucidate the relative influence of the surface features of atmospheric plasma sprayed coatings on acid corrosion responses and wear resistance, aiming at contributing to the development of a protective technique for electrical engineering.

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